This invention relates to sealing articles, and methods for making and using them. More particularly, this invention relates to sealing articles for forming a seal between a plurality of substrates and a bounded opening through which the plurality of substrates passes. In a particular aspect, this invention relates to articles and methods for forming a seal between a plurality of electrical conductors and a bounded opening, such as a tube, a connector backshell, a grommet, an opening in a firewall or other barrier, or a heat-shrinkable sleeve, through which the conductors pass; and the invention will be discussed primarily with respect to that aspect.
Forming an environmental seal between a substrate, such as an electrical conductor, optical fiber, and the like, and an opening through which it passes is a frequently encountered problem to which may solutions are known. The sealing problem becomes more difficult when the gap between the substrate and the opening is large and/or when two or more substrates pass through the same opening. Much difficulty is encountered with a plurality of substrates because all of the gaps between each of the substrates and between the substrates and the boundary of the opening must be sealed.
Lofdahl, U.S. Pat. No. 4,179,319, discloses a laminated sealing article comprising a layer of adhesive sandwiched between a pair of crosslinked, dimensionally heat unstable wafers of polymeric material. The article is provided with a plurality of apertures designed to receive a plurality of substrates therethrough; and the gaps between the plurality of substrates are sealed by heating the article to the recovery temperature of the wafers.
Meltsch et al., U.S. Pat. No. 4,438,294, discloses a sealing element for a cable entrance socket of a cable sleeve, where the element is made of a crosslinked thermoplastic material that is shrinkable to a previous shape when subjected to a shrinking process.
Akiyama et al., U.S. Pat. No. 4,647,716, discloses an article comprising a tubular outer member and a heat expandable compressed pre-foamed sealing member. When substrates, such as wires or wire bundles, are inserted in the tubular outer member and the article is heated, the sealing member expands to fill the space between the substrates and the tubular outer member.
Becker et al., U.S. Pat. No. 4,666,164, discloses a laminated sealing article comprising an adhesive layer, a heater layer, and a heat-recoverable foam layer, the thickness of which increases on heating. The article may be used to seal cable ducts and the like; where, on energizing the heater, the foam increases in thickness and forces the adhesive into sealing engagement between the duct wall and a cable.
Ono et al., U.S. Pat. No. 4,797,513, discloses a sealed funnel-shaped grommet for carrying a wire bundle or cable through a panel, where a sealing material, such as a two-part polyurethane resin, is put into the grommet from above to fill the space between a narrow cylindrical portion of the grommet and the wire bundle and gaps between wires.
Muller et al., U.S. Pat. No. 5,244,408, discloses a terminal housing with a wire entry system in which two closed-cell foam pads are mounted at each wire entrance port to provide strain relief and sealing around the wires.
The disclosures of these and other documents referred to throughout the specification of this application are incorporated herein by reference in their entirety.
It would be desirable to produce a sealing article, especially a sealing article for forming a seal between a plurality of substrates and a bounded opening through which the plurality of substrates passes, that could be prepared readily and inexpensively, would be readily usable, and would provide an effective seal between the plurality of substrates and the bounded opening when used.